11/3 What are Lewis structures?

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11/3 What are Lewis structures?

  1. 1. Launch: 11/3   Grab your binder and immediately take a seat! 1.  Draw the correct Lewis symbols for the following atoms: i.  hydrogen ii.  neon iii.  nitrogen iv.  bromine v.  strontium
  2. 2. Schedule   Monday (11/2): Covalent Bonds   Tuesday (11/3): Covalent Bonds   Wednesday (11/4): Covalent Bonds   Thursday (11/5): Covalent Bonds   Friday (11/6): Chemical Bonding Review   Monday (11/9): Chemical Bonding Review   Tuesday (11/10): Chemical Bonding Unit Exam!
  3. 3. Schedule   We don’t have time to waste!   Follow our 6 class rules   If you have a question, ask!   Ask your partner   Ask me
  4. 4. What are Lewis structures? Mr. Heffner 11/3/09
  5. 5. Review: Octet Rule   Octet Rule:   all atoms want to have 8 valence electrons •  •  • •    like the noble gases Ne F •  •  •  •  • •  •  •  •  • •  8= 7=
  6. 6. Review: Covalent Bonding   To get 8, two nonmetals share electrons • •  • •  F F • •  • •  •  • •  •  • •  7= 7=
  7. 7. Review: Covalent Bonding   To get 8, two nonmetals share electrons Covalent • •  • •  F F Bond • •  • •  • •  • •  • •  8= 8=
  8. 8. What are Lewis structures?   Lewis structures are…   used to represent covalent bonds between atoms •  •  Ne •  •  Lewis Symbol •  • •  • 
  9. 9. What are Lewis structures?   Lewis structures are…   used to represent covalent bonds between atoms • •  • •  Covalent Bond F- F 2 electrons = dash • •  • •  Lewis Structure • •  • • 
  10. 10. What is a Lewis structure?   There is a 3-step process for creating Lewis structures: 1.  Draw Lewis symbol for each atom and count dots 2.  Arrange atoms so they all have a full octet   If more than 2 atoms, place first atom in center 3.  Count dots and convert shared pairs to bonds
  11. 11. Example Draw the Lewis structure for Cl2   Step 1: Draw Lewis symbol for each atom and count • •  • •  dots Cl Cl •  • •  • •  •  • •  14 dots • • 
  12. 12. Example Draw the Lewis structure for Cl2   Step 2: Arrange atoms so they have a full octet • •  • •  Cl Cl • •  • •  • •  • =•  8• •  8 =
  13. 13. Example Draw the Lewis symbol for Cl2   Step 3: Count dots and convert shared pairs to dashes • •  • •  Covalent Bond Cl-Cl 2 electrons = dash • •  • •  • •  • •  • •  dots 14
  14. 14. Example Draw the Lewis structure for NH3   Step 1: Draw Lewis symbol for each atom and count • •  dots •  •  •  N HHH •  •  •  8 dots
  15. 15. Example Draw the Lewis structure for NH3   Step 2: Arrange atoms so they have a full octet   If more than two atoms, place first atom in center • •  HN H • •  H is an exception to •  • •  •  H the octet rule 2= 8=
  16. 16. Example Draw the Lewis structure for NH3   Step 2: Arrange atoms so they have a full octet   If more than two atoms, place first atom in center • •  H-N-H • •  • •  •  - •  H 8 dots
  17. 17. Example Draw the Lewis structure for HCl
  18. 18. Whiteboards   Work in pairs   Trade-off marker every question   You have 60 seconds to draw the answer   Show all three steps!   Lift board only when prompted
  19. 19. H2
  20. 20. Br2
  21. 21. SH2
  22. 22. CH4
  23. 23. Practice Questions   Practice Questions worksheet
  24. 24. Exit Slip 1.  In order to achieve a stable octet, two nonmetals a.  form ionic bonds by transferring electrons. b.  form ionic bonds by sharing electrons. c.  form covalent bonds by sharing electrons. d.  form metallic bonds by sharing electrons.
  25. 25. Exit Slip 2.  See whiteboard.
  26. 26. Exit Slip 3.  Which of the following correctly identifies the Lewis structure for HF?
  27. 27. Exit Slip 4.  Bubble in A Then, draw the Lewis structure for HI
  28. 28. Exit Slip 5.  Bubble in A Then, draw the Lewis symbol for CBr4
  29. 29. Homework   Finish Lewis symbol and ions worksheet

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